It would be a job to tackle yourself if you are up to it. It is big and bulky very difficult to transport unless very local. A new or rebuild is going to cost a lot. I think it is something that could be tackled. Remove the top, get a truck to tie it in the bed and get home when it is quiet on the road. Get a buddy that has some glass or woodworking experience to help. I'd cut the top off as it is extremely thin approx 1/2 from the edge (assuming you get all the coring, closer if needed). The edge likely has fairing compound, so if you ding it up, just repair with it. My guess is a wheel saw or dremel type of tool could do the job. Work the top off (hopefully it peels off) and if it gets trashed, just rebuild. If the top comes off clean, you have very minor glass work to do. Recore and then lass the top on. Pay attention to weight, you want a lightweight coring material. Maybe GW can tell you what they use? The top is seen very little so it doesn't have to be perfect in my opinion (glass job or gelcoat color for that matter). You could paint the underside if desired as well, you could even go with a totally different color if desired. I'd be more concerned with getting the coring done right and it totally sealed versus the cosmetics but that is just me.
I did a similar job when I reupholstered the combing bolsters, companion seat and aft seat. It seems daunting at first, but once you get into it, you'll find you can do it and it will be fine. If all else fails, seek some local help.
